The study of the normal function of living organisms and the means by which it is achieved.

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Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
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1answer
67 views

Death because of no radio waves

I read somewhere that a man dies if he is isolated from natural electromagnetic fields and waves. (I imply fields of radio frequencies and below.) Is it true?
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43 views

How well do we notice asynchronicity?

I'm stopped at a stoplight and, with nothing to do, my thoughts wander to the timed don't-walk sign that governs any pedestrians who might wish to cross the street I'm driving along. I can see two ...
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3answers
477 views

How are our senses dimmed during sleep?

Our senses are not as sensitive during sleep compared to wake. There is an arousal threshold during sleep that only when it is overcome will it wake a person up. My question is how is this arousal ...
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2answers
369 views

The number of nipples (breasts) a species has?

Only mammals have mammaries and mammary glands. What evolutionary factors determines the number of mammaries (nipples/teats/breasts) a species has? Is it always an even number?
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1answer
168 views

Excretion of various wastes and water requirement

A common fact is that Ammonia, Urea and Uric acid are the most common excreted metabolites and their removal needs varying amount of water, highest for ammonia (hence suited only for aquatic animals) ...
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65 views

Sodium levels and blood pressure

Why does low $\ce{Na+}$ levels cause hypotension (low blood pressure). Alternatively, why does excessive intake of $\ce{Na+}$ cause hypertension or high blood pressure? From what I ...
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1answer
138 views

Is there a maximum pain threshold?

Is there a maximum threshold of pain a Human can experience, beyond which point there is no noticeable difference? I ask this question in part to better understand the definition of pain and its ...
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1answer
85 views

Body size, what are the evolutionary trade-offs?

Background Considering just the "Kingdom Animalia" branch of organisms. It is clear that bigger does not necessarily mean better - there is large variation in body size... From the 94 ┬Ám long ...
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1answer
54 views

How much can you learn about species variation from a skeleton?

I just read about the discovery of the 1.8-million-year-old human skull in Georgia, and how it suggests that early humans were all one species instead of distinct ones. Would an archaeologist ...
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1answer
19 views

Order of events in hibernation

Arrange this in sequence : i. Heat loss exceeds heat production. ii.As body temperature falls, heat loss decreases. iii.Body temperature equals environmental temperature. ...
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3answers
900 views

Does Darwin's Theory of Evolution refute Terence McKenna theory “Stoned Ape” theory of human evolution?

I haven't read it but I'm asking for a quick answer. As far as I know, Terence McKenna's theory of evolution in humans main concept is that a hominid has tried in their diet psilocybin mushrooms, and ...
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2answers
1k views

How do insects breathe?

Do ants even breathe? If they don't, how do they stay alive? On what resources do they depend upon to stay alive? How are they different form mammals?
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1answer
64 views

(Web)app to search metabolic/signalling pathways

I'm looking for an application where you can find pathways by selecting a chemical occurring in it. So, for example, selecting 6-phosphogluconolactone brings up the pentose phosphate pathway or any ...
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20 views

Amphibian blood circulation

In an amphibian blood entering the right atrium shows higher levels of oxygenation than that in left atrium when : A.It is hyperactivated B.it is hibernating C.it is submerged D.it is in the ...
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1answer
109 views

Why can CO2 be transported dissolved in plasma?

Is it because CO2 is more soluble in water or has it got to do with the alkaline pH of plasma ?I here mean only aqueous CO2 transport from body cells to lungs.
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1answer
144 views

Why does caffeine consumption cause one to urinate more?

What is the physiological mechanism behind the diuretic effect of caffeine?
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1answer
66 views

Why does hypertension occur in obstructive sleep apnea?

What is the physiological mechanism behind systemic hypertension resulting from obstructive sleep apnea?
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1answer
165 views

Understanding Membrane / Resting Potential from the perspective of ions?

From wikipedia article RESTING potential: "there is no actual measurable charge excess in either side. That occurs because the effect of charge on electrochemical potential is hugely greater than ...
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1answer
39k views

What causes random long white body hairs?

I'm sure many of you have experienced this - you scratch your back or brush your hand over your arm and find a ridiculously long thin white hair, sometimes as long as 3 or 4 inches. I know a few ...
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1answer
64 views

Attachment of muscles during molting in insects

Normally, insects' muscles are attached to their exoskeleton but what happens to this attachment when they are moulting? Sorry if this is an extremely silly question but I have wondered about it for ...
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54 views

Competition for mates in sea horses

This source here ...research has shown that it is STILL the males that compete for females. says that male sea horses compete for mates but this source here Females exhibit a ...
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1answer
84 views

How does Humira work when injected into patients with rheumatoid arthritis?

OK, I have rheumatoid arthritis and I've been injecting Humira 2 times a month for the last 8 months. As far as I know rheumatoid arthritis is simply an immune system disorder which makes the immune ...
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0answers
51 views

Why delayed Power nap might degrade our night sleep?

Recently in the research areas we come across the term "Power Nap" which says after a nice lunch it would be nice to get a nap for 20-30 minutes which will make the body relaxed and fresh afterwards. ...
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1answer
95 views

cellular respiration

What are the effects of addition of these chemicals to actively respiring cells ? Which of them would lead to INHIBITION of aerobic respiration ? Would cytochromes be actually taken up by cells ? ...
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2answers
1k views

Is there any use of CO2 in human body?

We all know CO2 as a waste product of metabolism . Does CO2 have any helpful role , apart from having a role in pH of blood ?
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1answer
54 views

Antibody production in secondary immune response

Can IgG antibodies be produced in the secondary immune response without the help of T cells? Is the affinity of antibody for antigens higher during secondary immune response?
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1answer
55 views

Alternating Ovulation

I have often heard that right and left ovaries alternate in releasing ovum. Is it always true? What controls this rhythm? Is it simply because the other ovary is unresponsive to LH or FSH? If so, ...
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1answer
86 views

Need of Creatinine Phosphate

In muscle cells most of the ATP's phosphate is with creatinine phosphate. So why is the displacement of the phosphate group done ? Is it because creatinine phosphate would give it's phosphate more ...
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1answer
50 views

Effect of arteriole dilation on vein

If an arteriole leading to a capillary bed is dilated will the pressure in the vein coming out from the bed decrease ? Will the velocity of blood in the vein change ?
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1answer
339 views

Which is the tissue damaging agent in krokodil (street desomorphine)

I've just read about krokodil and saw some quite hideous pictures about what it does to the human body. I guess just desomorphine alone wouldn't have this effect. Which ingredient(s) causes the ...
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1answer
124 views

What happens in the synapse when cocaine administration occurs in the human brain

As far as i know when you accept cocaine in your blood some cocaine molecules reach some synapses in your brain and fill some Reuptake tunnels preventing the cell to simply "do not know that fired ...
5
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1answer
193 views

Skeletal muscles in clam

Although skeletal muscle fatigues fairly rapidly, clams have a protein called paramyosin that allows them to sustain contractions for up to a month. What might be the role of paramyosin at the ...
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0answers
62 views

Harmful effects of radiation from cell phone towers? [closed]

As per this article - http://www.thehindu.com/news/national/mumbai-citizens-link-cancer-to-cell-phone-towers/article5139166.ece , people living adjacent to cell phone towers claim to have developed ...
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1answer
18k views

Why is coffee a laxative?

How does caffeine (or any additional agents) act as a laxative when ingested? I'm interested in the metabolic/signaling pathway.
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1answer
51 views

Which fish will have more developed gills?

A fish lives at the depth of 1000-2000m and another at the depth of 200-700m. Which of them would have a more developed gill system ?
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1answer
98 views

All or none phenomenon

Let's say that the threshold potential of a neuron is +40 mV to make a muscle twitch. Now suppose we have two signals of +20 mV. So, this signal will cause the twitch in muscle because it has reached ...
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1answer
105 views

Is the resting state of the forearm in the pronated or supinated position?

It seems to me that my forearm is naturally in a more pronated position than the anatomic (supinated) position and that it actually takes work to make it hold the supinated position. Anyone an expert ...
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2answers
1k views

What is the genetic basis of blood type (ABO) system?

What is the genetic basis of the A/B/B+/O/etc. blood type system? Are there definitive loci that correspond to each or can multiple different genotypes produce the same antigen profile? Also, is the ...
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1answer
254 views

Can food swallowed when a person is upside down reach the stomach?

If a person positions himself upside down and swallows food, will it reach the stomach against gravity? If so how?
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1answer
90 views

Why do bats huddle during late fall?

In the late fall, bats hibernate in clusters with many bats pressed together and holding on to one another. Which of the following supposed advantages of huddling behavior is, in reality, not true? ...
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1answer
666 views

Are there more/less favourable phases of menstrual cycle to donate blood?

I was wondering whether it makes a difference when during the menstrual cycle a female is donating blood in terms of: Blood quality (iron or hormones levels) Her health/safety I am aware that ...
14
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3answers
368 views

Are human fetuses more likely to be male?

Question: From a physiological point of view, when sex is determined in a human fetus, is it equally likely to be male or female? Studies in this area typically measure age at birth, where the data ...
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1answer
83 views

Why pouring salt in the wounds is painful?

Pouring salt in the wounds is so painful. I am sure you all experienced this. whats happend there?
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954 views

What are potential side effects of myostatin inhibitors?

Myostatin inhibitors, which are being developed to treat muscle wasting diseases like muscular dystrophy, are likely to be abused by athletes. What are the potential long-term side-effects of taking a ...
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3answers
150 views

How does one maintain balance sleepwalking?

Anectodal. Feel free to shoot it down. Walking is an acquired skill; As far as I'm concerned exhaustion causes disorientation. Even after waking up it sometimes takes a second or so to get balanced. ...
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0answers
74 views

What are the physiological effects of wine?

I have read that alcohol in general and wine in particular can have advantageous as well as detrimental effects on human health. Is this true? What are the physiological effects of consuming wine in ...
6
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2answers
134 views

Would muscle fatigue still occur if aerobic conditions for a working muscle is maintained?

Put another way if the muscle is given everything it needs to contract and do work will it ever get tired or have a reduction in energy efficiency? As far as I understand muscles depend upon a ...
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2answers
170 views

Why is the human body able to repair a broken bone and not a heart muscle?

The human body can repair skin/organ laceration, fractures, even repair nerves - albeit the duration and rate of recovery differ. For instance: The burn scar on my arm from the hot soldering iron ...
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2answers
546 views

Physiological indicators of happiness and well being

If I understand it correctly, levels of serotonin in the brain can indicate if a person is happy. What other physiological measures indicate happiness or well being for a humans? I am looking for ...